1. Field of the Invention
This invention relates to a novel method of preparing certain phenol and 1-naphthol sulfamphthaleins and sulfamnaphthaleins useful as reagents in photography.
2. Description of the Prior Art
Various procedures have been reported for synthesizing 3-substituted-benz[d]isothiazole-1,1-dioxides and 3,3-disubstituted-2,3-dihydrobenz[d]isothiazole-1,1-dioxides from saccharin (3-oxo-2,3-dihydrobenz[d]isothiazole-1,1-dioxide) and from saccharin pseudo-chloride (3-chlorobenz[d]isothiazole-1,1-dioxide). As reported by A. Mustafa et al, J. Chem Soc., 1952, p. 1339, the treatment of saccharin pseudo-chloride with excess phenylmagnesium bromide gave the corresponding 3,3-diphenyl-2,3-dihydrobenz[d]isothiazole-1,1-dioxide in almost quantitative yield. Methyl-, ethyl-, n-propyl- and n-butylmagnesium halides were reported by these authors to react analogously. R. A. Abramovitch et al, J. Chem. Soc., Perkin Trans I, 1974(22), p. 2589, reviewed and reinvestigated the reactions of saccharins with alkyl and aryl Grignard reagents and found that either the 3-alkyl (or 3-aryl)-benz[d]isothiazole-1,1-dioxide and/or the open-chain tertiary alcohol, o-CR.sub.2 OH benzenesulfonamide wherein R is alkyl (or aryl) were obtained with one exception. When saccharin was treated with an excess of phenylmagnesium bromide in boiling tetrahydrofuran, 3,3-diphenyl-2,3-dihydrobenz[d]isothiazole-1,1-dioxide was obtained as the minor product together with the open-chain tertiary alcohol.
R. A. Abramovitch et al also investigated the reaction of saccharin and saccharin pseudo-chloride with organolithium compounds and found that the reaction of saccharin with alkyl- and aryllithium compounds, such as, n-butyllithium and p-methoxyphenyllithium in tetrahydrofuran at -78.degree. C. gave the corresponding 3-substituted-benz[d]isothiazole-1,1-dioxide exclusively. In addition to this general method for synthesizing 3-alkyl (or 3-aryl)-benz[d]isothiazole-1,1-dioxides, the authors reported that the reaction of the pseudo-chloride with organolithium compounds, such as, n-butyllithium in tetrahydrofuran at -78.degree. C. gave the corresponding 3,3-disubstituted-2,3-dihydrobenz[d]isothiazole-1,1-dioxide as the major product.
Besides the reactions with Grignard and organo-lithium reagents, Friedel-Crafts reactions with the saccharins also have been disclosed. Dutt, J. Chem. Soc., 121, p. 2389 (1922) reported the condensation of saccharin with aromatic amines and phenols in the presence of concentrated sulfuric acid and also in the presence of fused zinc chloride. The resulting condensation products with saccharin were named "sulfamphthaleins" by analogy to "phthaleins" and "sulfonephthaleins". Though the structure of 3,3-di(4'-hydroxyphenyl)-2,3-dihydrobenz[d]isothiazole-1,1-dioxide (named "phenolsulfamphthalein") was assigned to the condensation product obtained with saccharin and phenol, it has been determined that the compound corresponding to the proposed structure has properties different from those reported, for example, colorless rather than pink in alkali and also, that the compound corresponding to the structure given could not be synthesized by repeating the procedures reported by Dutt.
The present invention is concerned with a method of preparing sulfamphthaleins (3,3-disubstituted-2,3-dihydrobenz[d]isothiazole-1,1-dioxides) and sulfamnaphthaleins (3,3-disubstituted-2,3-dihydronaphtho[1,8-de]-1,2-thiazine-1,1-dioxides) derived from phenols and 1-naphthols which possess a carbonyl moiety in the 2-position, i.e., on the N atom of the sulfam(na)phthalein ring and with intermediates useful in the preparation thereof.